Block-signal system.



No. 799,816. PATENTED SEPT. 19, 1905.

H. E; WHITE.

BLOCK SIGNAL SYSTEM.

APPLICATION FILED FEB. 11. 1904.

Witnesses: Inventor:

Harold E. White mmiu. r Qumm 50.. FNOTWLIIMOGRAPHERS. WASNYNGYON o. a

rrnrrn s rnwnnr OFFICE.

HAROLD E. WHITE, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

BLOCK-SIGNAL SYSTEM.

Specification of Letters Patent.

Patented Sept. 19, 1905.

Application filed February 11, 1904:. Serial No. 193,086.

tems; and the object of my invention is to pro vide a novel signalsystem comprising as one of its elements a novel form of relay whichremedies a defect in operation which has existed in such systems asheretofore arranged.

In a block-signal system in which home and distance signals are used itis customary to operate the relays for the home signal for a given blockfrom the same source of current which operates the distance-signal forthe following block, the home signal being controlled by an ordinaryrelay the operation of which depends merely on the flow of currentregardless of direction and the distance-signal being controlled by apolarized relay the operation of which depends upon the direction of thecurrent. In this arrangement in order to secure the proper operation ofthe polarized relay it is necessary that the current through it shouldbe reversed whenthe distance-signal is to operate. This necessitatesareversal of current through the relay for the home signal also, andduring the reversal of flux there is an instant when the flux is zero,which produces a momentary shifting of the home signal. This shifting ofthe home signal may under some circumstances cause the engineer of anapproaching train to stop his train wholly unnecessarily. By myinvention this shifting of the home signal upon the operation of thedistance-signal is done away with and the chance of needless stopseliminated.

My invention will be best understood by reference to the accompanyingdrawing, in which A A A represent three blocks of a railway system.

B and B represent two semaphore-posts at the entrance to blocks A and A,respectively. Each semaphore-post carries a home and distance signal,(indicated by Hand D, respectively.) Thus the home signal for block A isindicated by the semaphore-arm H on sema phore-post B. Thedistance-signal for the same block isindicated by semaphore-arm D onsemaphore-post B. The drawing indicates the position of the signals onthe assumption that a train is in block A. The relay E isshort-circuited, allowing its armature e to fall. This opens the circuitof the operating mechanism for the home signal H, allowing the signal togo to danger position by gravity. The operating mechanism for signal His merely indicated by m, since many forms of electrical operatingmechanisms are well known in the art and form no part of the presentinvention.

Home signal H controls by its movement reversing-switch S in the circuitof battery b, which supplies the current for the relays connected toblock A. When home signal H is in the danger position, switch S is inthe proper position to produce a flow of current through polarized relayF of proper direction to deenergize the relay and to open the circuit ofthe operating mechanism at of distance-signal D. Thus home signal H anddistance-signal D are in the proper position to show the presence of atrain in block A. Current is flowing through relay E, which operatesregardless of the direction of currentflow. Relay E thus holds itsarmature up and maintains the circuit of operating mechanism m closed.Home signal H is accordingly held at safety, properly indicating thatblock A is clear. Now assume that the train in block A is passing out ofthe block and into the one beyond. The short circuit is removed fromrelay E, which draws up its armature e and closes the circuit of operating mechanism m, which restores signal H to safety. As signal H moves tosafety position it draws up switch S and reverses the direction ofcurrent through the trackcircuit A. Polarized relay F is thus energizedand draws up its armature f and operating mechanism a restoresdistance-signal D to safety. Signals Hand D are then in the properposition toshow that block A is clear; but in reversing the currentthrough relay F the current through relay E is also reversed. Thisproduces a reversal of flux in relay E,during which there is an instantwhen the flux is zero. At this instant armature 0 falls, opening thecircuit of operating mechanism m, and consequently signal H goes todanger by gravity. Although signal His restored to its proper positionthe next instant, there is a chance that the engineer of an approachingtrain may glance at the signal at the instant it goes to danger. Uponseeing a home signal at danger the engineer may apply theemergency-brake, thinking a train to be in the block he is entering,while in reality the train is two blocks beyond, and a stop is whollyunnecessary. This defect in the operation of the system is eliminated bythe novel form of relay whichI employ for controlling the circuit of theoperating mechanisms for the home signals.

each consist of an E-shaped magneticcore, forming with the armature twomagnetic parts or circuits, on one part of which is mounted the coil 2',which is connected to the track-circuit. The coil '5 corresponds to therelay-operating coil as ordinarily used. In addition to coil two othercoils j and 7a are placed upon the core E. Coil j is placed on the sameportion of the core as coilz' and being in inductive relation theretoacts as asecondary for coil z' and is energized by any fiuctuation ofcurrent in coil '5. Coil k, which is mounted on the other part of thecore forming the second magnetic circuit, is connected in series withcoil j and is traversed by any current induced in. coil j. The operationis then as follows: Assuming the circuit of coil 2' to be openedsuddenly, the variation in magnetic flux produced by the suddenvariation of current induces an electromotive force in coil which causesa current to flow through coil This current produces a magnetization ofthe portion of the core on which coil is is mounted, which is displacedin phasefrom, the magnetization produced by coil 2' and maintainsarmature c in its raised position during the instant that themagnetization of coil '6 passes through its zero value. The effect ofcoil is is of course only instantaneous; but by the time its effect hasdied away coil is again energized and continuously maintains armature ein its raised position. The effect of coil is therefore serves to bridgeover the instant during which coil is deenergized by the reversal ofcurrent. Consequently all danger of the signal controlled by relay Egoing to safety position upon an instantaneous reversal of current iseliminated and a serious defect in operation is removed- While I haveshown a simple form of relay well adapted to secure the object of myinven tion, it will be understood that its formlmay be considerablyaltered without departing from the spirit of my invention. For instance,although I have shown two magnetic circuits having onepart in common, itis not necessary that they should possess this feature, and the shape of.the magnetic circuits may be much altered without affecting theoperation. Accordingly I do not desire to limit myself to the particularconstruction and arrangement of parts here shown, since changes which donot depart from the spirit of my invention and which are within the Itwill be seen from the drawing that relays E and E'- scope of theappended claims will be obvious to those skilled in the art.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is- 1. In combination, an electric circuit, a

' switch member adapted to open said circuit,

a relay adapted when energized to maintain said switch member in itsclosed position, a coil adapted to energize said relay, and a secondcoil arranged to be energized upon a variation of current in thefirst-named coil and adapted tomaintain said circuit closed during aninstantaneous reversal of current in the first-named coil.

2. In combination, an electric circuit, two relay-coils, two magneticcircuits arranged to be energized by said coils, respectively, meansoperative upon the energizing of either coil for maintaining saidcircuit closed, a source of current connected to one of said coils, andmeans for energizing the other coil upon a variation of current in thefirst coil.

3. An electric circuit, two relay-coils, means operative upon theenergizing of either coil for maintaining said circuit closed, a sourceof current connected to one of said coils, means for reversing therelative connections of said coil. to said source, and means forenergizing the other coil upon a reversal of current in y the firstcoil.

L. In combination, two magnetic circuits, a movable armature adapted tobe restrained when either magnetic circuit is energized, a coil mountedon one of said magnetic circuits and connected to a. source of current,and a second coil mounted on the other magnetic circuit and arranged tobe energized upon a variation of current-flow in the first coil.

5. In combination, two magnetic circuits, a movable'armature adapted tobe restrained when either magnetic circuit is energized, a coilconnected to a source of current and adapted to energize one of saidmagnetic circuits, and means for energizing the second magnetic circuitupon a variation of currentflow in said coil.

6. In combination, two magnetic circuits, a movable armature adapted tobe restrained when either magnetic circuit is energized, a coil mountedon one of said magnetic circuits and connected to a source of current, asecond coil arranged to be energized inductively upon ranged to beenergized upon a reversal of current through the first coil.

8. A block-signal system, comprising ,a block-circuit, a source ofcurrent therefor, a polarized relay connected to said circuit, means forreversing the current through said circuit, and a non-polarized relayconnected to said circuit and comprising two magnetic circuits eachadapted when energized to maintain said relay closed, one of saidmagnetic circuits being energized by the current in said block-circuitand the other magnetic circuit being arranged to be energized during'areversal of said current.

9. A block-signal system, comprising a block-circuit, a source ofcurrent therefor, a polarized relay connected to said circuit,

means for reversing the current through said circuit, and anon-polarized relay connected to said circuit and comprising twomagnetic circuits each adapted when energized to maintain said relayclosed, a coil connected on one of said magnetic circuits and connectedto the block-circuit, a second coil arranged to be energized inductivelyupon a variation of current through the first coil, and a third coilmounted on the other magnetic circuit and connected in series with thesecond'coil.

In witness whereof I have hereunto set my hand this 9th day of February,1903.

HAROLD E. WHITE.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

